CVE-2026-68528: Concrete CMS

Medium severity, CVSS 6.0. EPSS: 0.4% chance of exploitation in the next 30 days.

Concrete CMS RSS Displayer block below version 9.5.3 rendered remote feed item titles without HTML escaping, resulting in stored cross-site scripting. An attacker able to control a title in a syndicated feed could execute script in the site origin for any visitor to the affected page, including administrators, without holding an account on that site. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.0 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks riodrwn for reporting.

Affected products

• Concrete CMS Concrete CMS

Published 2026-09-11. Last modified 2026-09-11.